Can You Overdose on Melatonin?

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Melatonin is a hormone that helps regulate sleep cycles. Although it is naturally produced by the body, it can also be taken in supplement form. When taken as a supplement, it is possible to overdose on melatonin.

This article discusses the uses, dosages, and side effects of melatonin, as well as the signs of an overdose.

woman taking melatonin before bed and drinking water

AnnaStills / Getty Images

What Is Melatonin Used For?

When a person’s sleep schedule becomes disrupted because of sleep disorders or jet lag, supplemental melatonin may be used to restore your sleep cycle and reregulate your body's circadian rhythm. The circadian rhythm is the body's 24-hour clock.

Other situations that may warrant melatonin use include those that may disrupt a person’s sleep schedule, such as shift work.

Melatonin’s Role in the Body

The naturally occurring type of melatonin is designed to aid in regulating your circadian rhythm. The hormone controls your sleep and wake cycles. When night falls, the brain receives the signal to start producing melatonin to ready the body for sleep.

However, because melatonin acts as an antioxidant, it also protects against certain cancers, as well as neurodegenerative disorders.

Melatonin Benefits

Melatonin can benefit you in a variety of ways, including:

  • Improving your sleep-wake cycle
  • Helping you fall asleep
  • Managing sleep disorders such as insomnia
  • Regulating the circadian cycle in people who are blind or work overnight
  • Preventing and treating jet lag
  • Preventing oxidation in the body, which can lead to inflammation, cell damage, and increase the risk of developing chronic diseases such as cancer
  • Aiding proper immune system functions by activating disease-fighting cells, known as natural killer cells and T lymphocytes
  • Decreasing your risk of developing neurodegenerative disorders such as Alzheimer’s disease

There continues to be debate about the effectiveness of taking melatonin supplements. More research is needed on the benefits and risks of long-term use.

Melatonin Side Effects

Occasional, short-term use of melatonin is considered generally safe. However, when a person chooses to take melatonin to help them sleep, they may experience some adverse effects. Side effects can include:

Is Melatonin Safe for Kids?

The Food and Drug Administration (FDA) hasn’t evaluated or approved the use of melatonin in children. There is also a lack of evidence surrounding any side effects involved in using melatonin at a young age. Because of this, you should always speak to your healthcare provider before giving your child melatonin.

Recommended Melatonin Dosage

The recommended dose of melatonin varies significantly depending on the person. This makes it difficult to determine how much you can safely use so that you don't overdose or take too much.

Factors such as age need to be considered when determining your dose. The optimal dose by age is:

  • Infants: 1 milligram (mg)
  • Children: 2.5 to 3 mg
  • Adolescents: 5 mg
  • Adults: Anywhere between 0.5 and 5 mg
  • Older adults: Starting dose between 0.3 and 2 mg 

Other factors such as weight and tolerance should also be taken into account when determining how much melatonin you can take.

Speak to your healthcare provider before starting melatonin. They will likely advise you to start at the lowest dose and work your way up if it is not working.

Uses of Melatonin

Typically, when someone wants to take a melatonin supplement, they are looking to correct their sleep pattern or get better and more restful sleep.

Research has shown that using melatonin for purposes aside from sleep is possible. One study looked at melatonin usage and anxiety prior to and following surgery and found that using melatonin prior to surgery helped reduce feelings of anxiety.  

Long-Term Effects of Daily Melatonin Use

Using melatonin is typically only recommended on a short-term basis. Long-term use of the supplement can cause the brain to become desensitized to it, which makes the supplement less effective over time.

One study looked at long-term use of the supplement and found that in six to 12 months following the first use of the supplement, the positive benefits associated with short-term use were gone.

Not all long-term effects are negative, however. Some research has found that people who have recently gone through menopause may experience better symptom management from daily use of the supplement.

Age may also play a role in the long-term effects. Research has found that adolescents beginning melatonin use before the age of 12 and who used the supplement for just over seven years had normal sleep quality a decade later.

Where to Buy Melatonin

Melatonin can be purchased over the counter at any drugstore, pharmacy, or sometimes, grocery store. It is also available at specialty supplement stores. Prior to choosing a melatonin supplement, you should speak to your healthcare provider to find out what dose would be best for you, as well as where to look for the highest-quality supplement.

Signs of Melatonin Overdose

Taking too much melatonin is not more effective and can have the opposite effect. This means that the sleep hormone may actually make it harder to fall asleep if too much is in your system.

Symptoms of Melatonin Overdose

Taking too much melatonin can lead to symptoms such as:

  • Headache
  • Changes in blood pressure
  • Drowsiness
  • Vomiting

People who have naturally low levels of melatonin in the body, like older adults, may be more sensitive to symptoms and side effects.

Medications That Interact With Melatonin

When taking new supplements, it’s important to consider possible drug interactions that may occur with the medications you take regularly. People who are on blood thinners, benzodiazepines, or epilepsy medications should heed caution prior to starting a routine with melatonin.

This isn’t to say that you cannot take melatonin if you require these medications. However, you should be under close observation by your healthcare provider during your treatment using melatonin.

Drugs that lower blood pressure can also cause a drug interaction when taken with melatonin.

Melatonin and Adverse Effects

Although adverse effects are rare, they can occur. Allergic reactions, fatigue, mood changes, and worsened cognitive performance can all be driven by melatonin use. Melatonin has also been shown to affect blood pressure and heart rate.

What Happens When You Overdose on Melatonin?

While the clinical research surrounding melatonin overdose is limited, overdosing is possible even if it’s not likely to result in serious health complications. The symptoms can range in severity depending on how much is taken and how the person’s body responds to the dose.

Treating a Melatonin Overdose

The most effective, first-line treatment option for melatonin overdose is eliminating the supplement from your routine. This will rid the body of the overabundance of the hormone and ease symptoms.

If the symptoms are serious, you may have to see a healthcare provider immediately so they can assess your symptoms and determine necessary treatment.

When to See a Healthcare Provider

You should see your healthcare provider before on melatonin. A provider will determine how much you should be taking and which supplement to buy based on your optimal dose.

Your healthcare provider will also be aware of other medications you’re taking. So, if you do want to start taking melatonin, your provider can develop a safe plan to do so.

Melatonin and Emergency Medical Care

If you’re experiencing symptoms of an allergic reaction, shortness of breath, chest pain, or a rise in blood pressure after taking melatonin, you should seek emergency health services immediately.

Outlook

Struggling with sleep issues is difficult, and using melatonin is relatively safe and effective. However, there are some factors that need to be taken into consideration prior to beginning so that you don’t take too much of the supplement.

Since it’s possible to overdose, knowing how much to take and whether there are other things you can do to boost your melatonin production naturally may be a helpful alternative. This is especially true if you’re unsure as to whether the supplement will help you, or if you are unwilling to risk the side effects of taking melatonin.

Summary

Melatonin is a naturally produced hormone that regulates your sleep-wake cycle. It also plays a role in immune function and acts as an antioxidant in the body.

In supplement form, melatonin is often used to address sleep issues, such as insomnia, or restore a proper sleep cycle in people that experience jetlag or work shift work.

When taken at low doses, melatonin is safe and effective. However, there are some associated side effects, including headaches, dizziness, and nausea. Taking too much melatonin can lead to an overdose. When an overdose occurs, people may experience symptoms such as daytime sleepiness, vomiting, and high blood pressure.

In rare cases, serious health consequences can occur, but clinical research surrounding melatonin overdose is limited. To treat melatonin overdose, the first step is eliminating use so that it can be excreted from the body and relieve symptoms.

A Word From Verywell 

Coping with sleep issues or changes in your sleep cycle can be challenging. Taking melatonin may be an effective way to restore your body’s ability to get good quality sleep. That said, you should follow the recommended dosage and watch for side effects to ensure that you don’t take too much. Always inform your healthcare provider before starting any new supplement regimen to ensure that it is safe for you.

Frequently Asked Questions

  • Can a melatonin overdose cause death?

    Although it is possible to overdose on melatonin, researchers have not yet encountered a dose that would be lethal. There also are no reports of death caused by melatonin. Typically, melatonin overdoses present with mild to moderate symptoms that correct themselves when the melatonin use is stopped.

  • What happens when you mix melatonin and alcohol?

    Taking melatonin and alcohol together is not advised. Alcohol is known to disrupt sleep patterns, which reduces the effectiveness of melatonin. In some cases, alcohol can also strengthen the effects of melatonin, leading to extreme drowsiness, dizziness, and an increased risk of accident or injury.

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Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Angelica Bottaro
Angelica Bottaro is a professional freelance writer with over 5 years of experience. She has been educated in both psychology and journalism, and her dual education has given her the research and writing skills needed to deliver sound and engaging content in the health space.